(a) Field of the Invention
The present invention relates to a common electrode panel, a manufacturing method thereof, and a liquid crystal display (“LCD”) having the common electrode panel, and more particularly to a transflective common electrode panel, a manufacturing method thereof, and an LCD having the transflective common electrode panel.
(b) Description of the Related Art
LCDs are one of the most widely used flat panel displays. An LCD includes a liquid crystal (“LC”) layer interposed between two panels each provided with field-generating electrodes. The LCD displays images by applying voltages to the field-generating electrodes to generate an electric field in the LC layer that determines orientations of LC molecules in the LC layer to adjust a polarization of incident light on the LC layer. The incident light having adjusted polarization is either intercepted or allowed to pass by a polarizing film, thereby displaying images.
LCDs are classified as either a transmissive LCD or a reflective LCD depending on the light source used by the LCD. The light source of the transmissive LCD is a backlight. The light source of the reflective LCD is external light. The reflective type of LCD is usually implemented in small or medium sized display devices.
A transflective LCD has been under development. The transflective LCD uses both a backlight and an external light as the light sources depending on circumstances, and is also usually implemented in small or medium sized display devices. The trans-reflective LCD includes a transmissive region and a reflective region in each pixel. While light passes through an LC layer only once in the transmissive region, light passes through the LC layer twice in the reflective region. Accordingly, gamma curves of the transmissive region and the reflective region are not coincident, and images are displayed differently in the transmissive region and the reflective region.
To solve this problem, the LC layer may be formed to have two different thicknesses (cell gaps) between the transmissive region and the reflective region. Alternatively, the trans-reflective LCD may be driven by two different driving voltages depending on whether the LCD is in a transmissive mode or a reflective mode.
However, when the two cell gap structure is applied, a thicker layer is required to be formed on the reflective region, thereby complicating the manufacturing process. Furthermore, since a high step is formed between the transmissive region and the reflective region, the LC molecules are aligned in a disorderly manner around the high step, thereby causing disclination in an image. Also, brightness reversion may occur in a high voltage range. On the other hand, when the method of applying two different driving voltages is used to solve the problem, gamma curves cannot be coincident due to the inconsistency between critical voltages for transmissive brightness and reflective brightness.